components/HelloCom. vue :
<template>
<div>
<h1>{{ message }}</h1>
<button @ click = " greet" >greet</button>
</div>
</template>
<script>
export default{
    date(){
        return{
            message:'Hello ,Vue3!'
        }
    },
    methods:{
        greet(){
            //$attrs接收父组件传给当前组件的name属性
            this.message ='Hello,'+ this. $ attrs. name +'!'
        }
    }
}
</script>
<style>
</style>